A No Background Check, No FFL Needed AR-15

This is something every AR enthusiast should be aware of, as well as those who are considering purchasing another or even their first AR's.  If you are planning on building your first or next AR-15 yourself, there are a few things you will need to be aware of before you start ordering parts.  Some parts must ship to a local gun store where you will have to fill out the appropriate paperwork and submit to a background check before you can take ownership of the part, while other parts can ship directly to your house via the mail. Let's begin!

An example of a super high-end, custom, Stripped Lower Receiver
 - the Seekins Precision Billet Lower

An example of your basic Mil-Spec, forged Lower Reciever
that has been completely assembled with a parts kit, stock and magazine

The AR-15 consists of 5 main part systems, within each part system their are many smaller parts that make this up.  These 5 main parts are: the Upper Reciever, the Lower Receiver, the Barrel Assembly, the Stock, and the Bolt Carrier Group. Out of these 5, the only one that must go through a licensed FFL (gun store or dealer), is the Lower Receiver (see picture to left). The reason for this is that this part houses the trigger group mechanism. Along with the trigger mechanism, the Lower Reciever also houses the magazine and magazine release button, the bolt release mechanism, the safety mechanism, the buffer, buffer tube, action spring, stock, and pistol grip. As you can see the main firing controls are located on the lower receiver of the AR-15 Weapon System.  You will see to the right, a picture of an assembled Lower Reciever.  AR Lowers can be purchased in either of the two ways, Stripped or Assembled. I prefer to purchase mine Stripped so that I may use my own selection of parts and springs to assemble the lower.  If you have never assembled an AR Lower, this is something that I recommend you do for your next project, as this can be a super rewarding as well as educational project. There are many things to be learned about firearms and how they function by putting together the trigger group and safety mechanisms. It also allows you to see how to remove the parts should some part ever stop functioning properly and need to be replaced, or if you want to remove all the parts for a very thorough cleaning or tuneup.

So far, we've seen that there are Stripped and Assembled AR Lowers, both of which must be purchased through or shipped through a Gun Store who must perform an ATF Background Check on the purchaser.  There remains yet, another format that one can purchase an AR Lower in, and this format is the reason for this posting.  Some manufactures offer what they call, an unfinished AR Lower or what is more popularly known as an "80% Lower", meaning that this Lower is only 80% of the way finished. This type of AR Lower has not had the area behind the magwell machined out yet. This area, is the section where the trigger group and safety mechanisms reside in a Completed/Assembled AR Lower. Since this type of lower can not be made functional without more machining performed first, the ATF does not recognize this type of lower as a firearm, so no background check is necessary to purchase one.  You read correctly, you can purchase these type of lowers on the internet or from a gun store for almost 25% less than your typical Stripped Lower, and it ships directly to you, no background check, no registration (if you live in a state that requires this), and no waiting period!  Unfortunately, we all don't have access to million dollar CNC machines, or fully equipped Machine Shops, so these lowers often prove useless to the average person.  However, in recent years, several new concepts have been developed to help make this type of lower easier to machine and easier to obtain. The most important tool needed for the Weekend Warrior attempting to finish machining the remaining 20% of an "80% Lower", would be a jig.  Several companies are producing these, some are better than others, and without one, I can honestly say that it is impossible to accurately mill out the remaining 20% of metal without access to a Machine Shop.  My favorite 80% Lower, and I have not personally ever purchased one, but have heard many good things, would be the JMT Polymer 80% AR-15 Lower Receiver & Jig, sold by Rainier Arms.  The reason this is my favorite, is due to a few unique characteristics. First, JMT built these lowers from a composite polymer, similar to those used in the frames of Glock handguns. Since this lower is Polymer and not a metal like Aluminum or Steel, it is much easier to cut and drill, as well as faster. Polymer AR-15 Receivers have gained

JMT's Polymer 80% AR Lower & Jig costs $95

The Jig properly assembled on the Lower,
 ready for a vise or drill press

popularity in the past couple years, and JMT's lower is by far one of the nicest looking, and strongest one available at the moment.  The main reason for using polymer in the construction of an AR is for weight savings. The most common commercially available composite AR-15 would be Bushmaster's Carbon 15, made from a Carbon Fiber composite polymer. As with anything, the polymer AR receivers do have their drawbacks when compared to metal, felt recoil is greater due to the lighter weight, the chances of breaking one are slightly higher than one machined from 7075 Aluminum, and some naysayers nag at the accuracy of a polymer AR.  JMT has taken steps to reduce these downsides, and they have done a fantastic job. The JMT Polymer lower is built thicker than the average Polymer Lower, increasing thickness of the sidewalls, similar to a Billet AR Lower, increases durability and accuracy. The second reason the JMT is my favorite Polymer Lower, is the fact that the manufacturer, JMT, includes the necessary Jig with the lower. Unlike other Jigs available, the JMT Jig is molded to clamp nicely over the Lower Receiver and in the correct spot, a Chimpanzee couldn't mess this up! Once the Jig is placed over the lower, and locked into place, you simply start drilling the appropriate holes. I recommend waiting to drill the trigger and hammer pin holes, as well as the safety selector hole until you have drilled out the inner section for the trigger group. This will ensure that when you drill the holes they are straight, as the amount of material you will be drilling through will be thinner than what it would be if you drilled these holes first. My third favorite trait of the JMT Polymer Lower is the fact that it has been designed to resemble the most expensive high-end custom, Billet Lower receivers available on the market. The magwell has a thick beveled edge running all the way around the bottom to ensure quick and smooth magazine changes. The front of the magwell has serrations machined into the lower to ensure a non-slip surface for gripping the weapon system under the upper at the front of the lower. JMT machined a wide, deep, and slick looking trigger guard into the bottom of the lower. Lastly, my final favorite aspect of the JMT Polymer Lower, is that JMT decided to just make a lower and not an entire Polymer receiver set (Upper and Lower). This basically makes the accuracy downside null and void. In an AR Weapon System, the accuracy aspects are almost fully a result of the Upper Receiver characteristics. The Upper Receiver includes the

A super high-end custom, AR Upper Receiver -
Seekins Precision Billet Upper Receiver.
Available at Rainier Arms.

complete action and firing mechanisms, as well as the barrel and gas system.  No matter what lower is used or what parts the lower was assembled with, it is the upper that determines whether or not an AR will fire, jam, shoot consistently, cycle the action, eject and extract the casings properly, and place bullets in tight or loose groups.  The only part that the lower plays in accuracy is that the upper and lower should fit snuggly together. A tight fit between the two eliminates play and ensures the action will cycle smoothly and accurately.  If I were building an AR-15 on a JMT Polymer lower, I would use a high-end Billet Upper Receiver with very thick walls. The thicker the better as this ensures a more accurate action and a tighter fit between upper and lower.  Along with this high-end Billet Upper Receiver, I would also make sure to purchase a Match or Ultra-Match grade barrel to ensure sub-MOA accuracy (tighter groupings when shooting - sub-MOA means all bullets are closer than 1" at 100 yards).

Daniel Defense Cold Hammer Forged, Chrome Lined
AR-15 Barrel made from the hardest and highest quality
Machine Gun Barrel Steel

 Obviously the Reciever and Barrel are probably the most important when building a tack driver but you must also realize that the remaining Upper Receiver parts are also important to ensure that your AR will function every single time, as needed, when needed.  A National Match Bolt Carrier Group, in Hard Chrome or Nickel Boron helps ensure consistent lockup and smoother, less pronounced recoil.  I always buy Billet Charging Handles with some sort of oversized or ambi latch, for this project I would consider this a minimum requirement and would quite possibly look at one of the two Steel Charging Handles available on the market right now. Steel Charging Handles, do not flex or bend at all making them almost invincible to one handed charging and the rigors of Combat. No matter what fore-end/rail system you choose to place over the barrel, I can tell you that you WILL want it to be of the Free Float type so that it does not interfere with the accuracy of the barrel.

A complete AR-15 on a finished JMT 80% Polymer Lower

When it comes to gas systems you really only have a couple choices, the basic gas system which we know from the past 50 years is a super reliable system, and/or a Piston Driven system which has been used in firearms even longer than the gas system but is fairly new to the AR Weapon System.  Everyone has their own opinions on the two gas systems, and both systems have their drawbacks as well as their benefits, but I can tell you from experience in shooting both types of systems that neither has ever been more accurate, more consistent, or more reliable than the other, both will jam from time to time, both will get dirty, and both will need repairs (although, the Gas Impingement System will often need less repairs as there are less moving parts).  At this point all of my AR Weapon Systems are Gas Impingement, however, I do have a build planned for the future that will be a Piston Driven System. I honestly feel that if one has the ability to own a few AR-15s it would benefit that person to have both Gas Systems available to choose from.

Wrapping it all up, you now have an idea of what type of parts you should put together to produce a quality upper for pairing with a polymer lower.  We learned of the many great features JMT has incorporated into their 80% Polymer Lower, and where you can obtain one, as well as how to finish machining one so that it can be assembled into a complete AR-15.  Even if your not interested in a polymer AR, it is interesting to know that one can be purchased without any background check, it just takes a little extra work. Be sure and check out Rainier Arms for high-end and custom AR-15/M16 parts and check out Brownells, for the world's largest selection of gun parts and gunsmithing equipment.